THE MAJOR OBJECTIVE OF THE STUDY WAS TO FORMULATE A SOUND, EFFECTIVE AND WORKABLE METHOD OF SCREENING CHILDREN FOR PLACEMENT IN SPECIAL CLASSES FOR THE MENTALLY RETARDED. THE PROJECT WAS A PILOT STUDY OF APPROXIMATELY 5,000 ELEMENTARY SCHOOL CHILDREN IN GRADES 1 THROUGH 6 IN 2 REPRESENTATIVE COUNTIES. TEACHER AND PRINCIPAL REFERRALS WERE SECURED ON THIS SAMPLING, AND GROUP INTELLIGENCE AND GROUP ACHIEVEMENT TESTS HAVING THE LOWEST RATINGS WERE SELECTED FOR FURTHER INTENSIVE STUDY, INCLUDING INDIVIDUAL VERBAL AND PERFORMANCE PSYCHOMETRIC EXAMINATIONS, SOCIAL CASE HISTORIES, AND GENERAL AND SPECIAL MEDICAL EXAMINATIONS. ALL PERTINENT INFORMATION ON EACH PUPIL WAS IMPORTANT IN CONSIDERING HIM FOR PLACEMENT IN A SPECIAL CLASS. THE FIVE FACTORS USED IN THIS STUDY OR SIMILAR CRITERIA WERE APPLIED TO ALL OF THE PUPILS IN THE SCHOOL POPULATIONS SURVEYED. RESULTS OF THE STUDY IMPLIED THAT--(1) PUPILS IDENTIFIED BY ALL THE FACTORS MAY BE REGARDED AS ELIGIBLE FOR ADMISSION TO SPECIAL CLASSES UNTIL EVIDENCE TO THE CONTRARY IS SECURED, (2) PUPILS IDENTIFIED BY ONLY FOUR OF THE FIVE FACTORS MAY BE REGARDED AS HAVING A 90-PERCENT CHANCE OF BEING MENTALLY RETARDED, (3) PUPILS IDENTIFIED BY ONLY TWO OR THREE REFERRAL FACTORS SHOULD BE CONSIDERED DOUBTFUL PROSPECTS FOR CLASSES FOR THE MENTALLY RETARDED, (4) NO PUPIL SHOULD BE ADMITTED TO A CLASS FOR THE MENTALLY RETARDED UNTIL HE HAS BEEN ADMINISTERED AT LEAST ONE VALID INDIVIDUAL INTELLIGENCE TEST, (5) PROSPECTIVE PUPILS FOR A SPECIAL CLASS SHOULD HAVE AN HISTORICAL RECORD MADE OF PHYSICAL DEVELOPMENT BASED ON AN EXAMINATION BY A COMPETENT PEDIATRICIAN, AND (6) REPORTS OF PHYSICAL EXAMINATIONS AND TESTS OF SOCIAL MATURITY AND EMOTIONAL HEALTH CAN BE VERY HELPFUL IN TEACHING AND REMEDIAL WORK. (GC)